The eye of the marine gastropod, Strombus luhuanus, is anatomically well developed, visually important, and exhibits interesting light-evoked electrical activity. Following amputation of the eye, a new and apparently normal eye is regenerated in its place. The proposed research is primarily concerned with ontogeny of the mechanisms underlying the processing of visual information during regeneration of the eye of Strombus. It focuses on a variety of problems concerned with photoreceptor excitation, neuronal interactions between retinal elements, and the innervation of the regenerating retina. Electrophysiological recording and stimulating techniques, combined with methods for photic stimulation, will be used to examine extracellular potentials from the retina and optic nerve, and intracellular electrical events from single retinal neurons. Anatomical studies employing light and electron microscopy and techniques for staining single neurons with intracellular dye will accompany the electrophysiological investigations. The proposed research promises to further our understanding of the development of sense organs and nervous systems in general, as well as to help clarify the mechanisms involved in visual information processing.